KR100566349B1 - Method of detecting atmospheric weather conditions - Google PatentsMethod of detecting atmospheric weather conditions Download PDF
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- KR100566349B1 KR100566349B1 KR1020007004343A KR20007004343A KR100566349B1 KR 100566349 B1 KR100566349 B1 KR 100566349B1 KR 1020007004343 A KR1020007004343 A KR 1020007004343A KR 20007004343 A KR20007004343 A KR 20007004343A KR 100566349 B1 KR100566349 B1 KR 100566349B1
- South Korea
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- probe volume
- bad weather
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- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/88—Lidar systems specially adapted for specific applications
- G01S17/95—Lidar systems specially adapted for specific applications for meteorological use
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using infra-red, visible or ultra-violet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
- G01N21/45—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods
- G01N21/455—Schlieren methods, e.g. for gradient index determination; Shadowgraph
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
- G01S15/88—Sonar systems specially adapted for specific applications
- G01S15/885—Meteorological systems
- G01—MEASURING; TESTING
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/86—Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
- G01—MEASURING; TESTING
- G01W2001/003—Clear air turbulence detection or forecasting, e.g. for aircrafts
FIELD OF THE INVENTION The present invention relates generally to a detection system for detecting a bad weather condition that is dangerous for an aircraft to fly, and in particular, all clear turbulence, windshear that are proven to present a dangerous situation to the aircraft and its passengers in the near future. For sensors that optically characterize ring-eddy turbulence that emits sound waves generated by aviation hazards, such as instant gusts and wake vortex generated by aircraft. will be. Information gathered from the system provides early warning to pilots and ground personnel.
In the past, various proposals have been proposed to provide aviation pilots and ground base personnel with information about dangerous weather conditions. Some of these proposals include laser detectors that detect atmospheric conditions such as temperature, water vapor content, and flight speed as indicators of weather conditions. These conventional laser-based systems have not been widely accepted commercially.
Other types of detection systems, such as weather sound detection and ranging (SODAR) and weather radar, have been used, but these systems experience reduced energy backscattering under very coarse mixing of air masses to be detected. Because weather conditions are measured, they do not provide all weather characteristics. Thus, these systems become useless during the bad weather conditions that are really needed. Similarly, weather lidars are more accurate than weather radars, but worse in weatherability.
Thus, a high degree of aviation safety is required due to recent aviation catastrophes or catastrophes that remain unexplained or remain unexplained due to chunky turbulence, storms, wind shears and momentary gusts.
Since the 1970s, it has been recognized that the atmospheric phenomena include or occur in acoustic patterns or signals in the form of very low frequency sound waves traveling relatively long distances that are relatively unhindered by ambient weather or other atmospheric phenomena. This sound generation phenomenon, known as ring-eddy vortexing, and its associated velocity cycles and unstable flow fields produce radiated sound that resembles the waveform generated when a pebble is thrown into water. The ring created by the thrown pebbles is similar to the form of acoustic patterns associated with severe thunderstorms, wake vortex and other chunky turbulence.
It has also been publicly known that moving objects such as ships, submarines or underwater animals generate and radiate sound waves. Such sound waves can be detected by a laser sensing system using free space or waveguide light beams to indicate the presence and location of underwater objects emitting or reflecting them. Such a system is shown in Jacob, US Pat. No. 5,504,719.
However, in spite of such prior notice, anyone presenting or successfully using a laser detection system that responds to sound waves generated by bad weather or wake vortex conditions to provide advanced warnings to aircraft pilots or airborne ground personnel. none.
Funk, Jr., US Pat. No. 3,693,015 is a prior art of the present invention. In addition, Palmer US Patent No. 5,221,927 also corresponds to the prior art of the present invention. U. S. Patent No. 5,221, 927 discloses a method for remotely sensing a standby state, which comprises transmitting a rider beam from the rider transmitter to the air in a predetermined direction, and transmitting sound waves from the acoustic transmitter in line with the rider transmitter. And transmitting to the air, and determining a specific air condition by measuring a change in sound waves of the rider reflected and returned to the air.
SOCRATES system of the present invention has the same purpose as above.
It is a primary object of the present invention to provide a novel method and apparatus for detecting bad weather conditions in the air that pose a hazard to a flying aircraft.
Another object of the present invention is, for example, in bad weather conditions such as chunky turbulence, wind shear, and severe winds, microbursts and / or wake vortices or fierce whirlwinds that erupt to runways along mountainous access paths, or engines of approaching aircrafts. Even noise, or a missile fired by a terrorist, is detected by optically detecting sound waves generated in accordance with these bad weather conditions or other conditions, and then new signals to provide early warning signals to pilots and / or ground personnel of the aircraft. One way is to provide it.
Another object of the present invention is to use one or more laser beams to detect sound waves generated by bad weather conditions in the atmosphere, giving enough time for pilots and / or ground personnel to take corrective action so that aircraft can avoid dangerous weather conditions. To provide a new way to do this.
It is yet another object of the present invention to provide light to these probe volumes in the presence of bad weather or wake vortex conditions in an atmospheric area that maintains a significant distance from the probe volume of the atmosphere containing light reflecting materials such as particles, aerosols and dust. It is to provide the above novel method of directing a beam. As a result, the novel system of the present invention provides sufficient time for the pilot or ground personnel to take corrective action to avoid dangerous operating conditions.
It is yet another object of the present invention to provide a novel method with the alternative mode of action of directing a light beam to a fully reflector or partial light reflector, wherein these reflectors are in a region of the atmosphere that maintains a significant distance from their light beam. Efficiently returns light along an optical path where the speed of light changes due to the arrival of sound waves from bad weather or wake vortex present in the. The speed of light that fluctuates along each optical path to light in a vacuum is directly involved in the change in the refractive index, as opposed to the change in particle motion. In applications where it is not appropriate to attach a physical retroreflector to reflect the energy of light, the binding of particles that change through their motion to reflect the energy of light and bring about a change in refractive index may be caused by distant weather conditions or wakes. Contribute jointly to significantly different information about the arrival of sound waves from the vortex state, but each along an axis that matches each other or is perpendicular to the direction common to the transmitting and returning light beams, or at right angles to that direction, respectively. Gives its maximum response.
The object of the present invention is by the aforementioned bad weather conditions or states of wake vortex, where the light beam strikes a moving particle and / or maintains a significant distance from the local optically defined region where the light beam intersects the sound wave. This is achieved using the corresponding light beam propagating free space, except when interacting with pressure to induce a change in refractive index due to the emitted sound waves. This object can be achieved even by using light waves guided by optical fibers. This optical fiber also emits sound waves emitted by the sound source generated by a bad weather condition or a wake vortex state in which optically defined local regions in the place where light propagates through free space are changed, which are equivalent in path length and light velocity, respectively. Alternate particle motion and refractive index changes that occur when intersecting with.
It is yet another object of the present invention to provide a novel laser detection system as described above, which is installed directly on the aircraft to provide information directly to the ground or close to the airport or near the airport runway. Provide information to ground personnel leading to landing ingress and landing or takeoff and elevation by one or more aircraft.
Other objects and advantages will become apparent from the following detailed description of the invention and the accompanying drawings.
1 is a schematic diagram of a laser system of the present invention installed on an aircraft to detect sound waves generated in bad weather conditions in a distant atmosphere. Similar simple systems may be installed on the ground.
FIG. 2 is the laser system of the invention shown in FIG. 1 capable of detecting particle motion in the probe volume from sound waves generated in distant bad weather conditions using an array of light beams operating on associated probe volumes in the atmosphere. Schematic top view of the house.
3 is a block diagram generally illustrating the photo / electric components associated with each probe volume and forming part of the array shown in FIG.
4 is a schematic representation of a ground-based embodiment of the laser system of the present invention for measuring a change in travel time of a light beam with a change in refractive index of the atmosphere due to sound waves generated in dangerous weather and wake vortex conditions.
5 is a sectional view along line 5-5 of FIG.
FIG. 6 shows a second embodiment of a terrestrial known system in response to a change in travel time of a light beam;
FIG. 7 is a sectional view along line 7-7 of FIG. 6;
1 to 3, the novel laser detection system 10 is installed in front of the aircraft 11 and includes a laser 12 and a beam splitter 38. The beam splitter 38 is located in the atmosphere via a focused telescope 74 at a remote sensing range A, e.g., 0.5 km or less from its telescope 74, in the atmosphere or focus volume. It is suitable for providing a plurality of transmission beams 34a, 34b, 34c, etc. to an array (16a, 16b, 16c, etc.). The number of transmit beams 34 and probe volumes 16 may vary, but preferably, 128 probe volumes are arranged in a three-dimensional branch cone configuration in front of the aircraft 11. The probe volume may be used to detect a very low frequency infrasound generated from a dangerous weather condition in the atmosphere at a stand-off distance B, for example, 100 kilometers from the front of the aircraft 11. It acts as a virtual microphone. An acoustic array of virtual microphones is proposed to include, for example, two steradian spherical caps centered in a straight line from the front of an aircraft or airborne base system of an aerial system. The range to be replaced by the probe volume to reject backlobe responses from the aircraft direction or from behind the ground-based system is a similar spherical cap of a virtual microphone that maintains a constant spacing behind the advancing array at about 1/4 of the acoustic wavelength. It must be formed to form an array, and such apertures are designed. Such dual spherical cap arrays can be designed to accommodate nested sub apertures filled with virtual microphone gaps suitable for other acoustic frequency subbands.
Backscattered modulated beams reflected from particles moving within the probe volume are collected by a multi-channel receiver in a charge coupling device (CCD) 87 suitable for coherent light mixing and then processing. By providing early warning to the pilot, the pilot can take the necessary corrective action. Since the weather-related sound is emitted almost continuously by the virtual microphone, the propagation time makes no sense because the emitted sound package is heard just 2-3 minutes earlier. For example, although it takes 5 minutes for the sound wave 20 to proceed to Mach 1 and arrive at the 102 km distance allowed at the time of reception, for example, the pilot of an aircraft that also proceeds at Mach 0.5 speed is about 10 minutes. You will be given early warning early. This is because the aircraft will narrow 51 kilometers before it receives the sound emitted from the first 153 kilometers away from the dangerously swirling air mass, and it will take another 10 minutes before meeting with the air mass while continuing to Mach 0.5. This 10 minutes is enough time to take corrective action, and this acoustic emission and reception distance will be reduced by more than half before reaching a critical early warning situation.
Referring to FIG. 3, the laser detection system 10 of FIG. 1 may be regarded as a sensor for optically characterizing ring-eddy turbulence emitting sound waves. The laser detection system 10 operates at about 1.57 or 2 micrometers and produces a light dump 22 that is executed by an electro-optical (EO) pulse modulator 24. State laser 12. The modulator 24 is controlled by a pulse coded E-O driver 26, the transmission timing of which is controlled by the platform operation (advection / convection) longitude time interval tracking device 28. The pulsed light beam 30 generated from the E-O pulse modulator 24 is divided into a transmission beam 34 and a reference beam 36 through the partially reflected beam splitter reflector 32. The beam splitter 38 splits the transmission beam 34 into a plurality of transmission beams 34a, 34b, 34c, etc. in correspondence to the detected number of probe volumes 16a, 16b, 16c, and the like.
The reference beam 36 is reflected by the reflector 42 into the path length matching assembly. The path length matching assembly is a piezoelectric fiber path length " stretch that responds to the optical feedback fiber coupler 44, the fiber bulk time delay coil 46, and the electronic feedback signal 50 generated from the tracking device 28. Bragg-cell that offsets the frequency of the reference beam for the next heterodyne that mixes the delayed device 48 and the matched reference light beam 54 with the beam returned from the probe volume. ) Optical fiber to optical coupler 52 which emits to up / down frequency shifters 56 and 58. Although the outer control loop is not shown, it receives the demodulated phase rate output signal 102a (described later) and passes it to the outer loop average filter and frequency synthesizer. The frequency synthesizer will provide a frequency selected from the discrete frequency tonal, which discrete frequency tonal is associated with controlling the surface acoustic wave modulation of the offset frequency of one of the Bragg-cell up / down frequency shifters 56, 58. It is precisely synchronized to the clock frequency and maintains a narrow frequency interval. After variable gain amplification and power amplification, the control and amplification frequency synthesis tonals selected closest to the instantaneous Doppler average represented by averaging the voltage portion in the phase rate output signal 102a are connected to an external average-Doppler compensated feedback loop. Is fed back. A plurality of such average-Doppler compensated feedback loops are similarly applied to each of the phase rate output signals 102b, 102c, etc., from different probe volumes.
The reference beam 54 passes through the beam splitter 60 and is divided into a plurality of reference beams 54a, 54b, 54c, etc. corresponding to the number of probe volumes 16 and the number of transmission beams 34a, 34b, and the like. do.
The optical path and associated light processing components for the transmit beam 34a, reference beam 54a and probe volume 16a are shown in FIG. The same optical path and circuit elements (not shown) are provided to the probe volumes 16b, 16c, etc., the transmission beams 34b, 34c, etc., and the reference beams 54b, 54c, etc.
The transmit beam 34a from the transmit beam splitter 38 passes through the beam deflector 70, beam expander 72 and concentrated telescope 74 to the desired light from the concentrated telescope 74. It is completely changed to the probe volume 16a located in the acoustic remote sensing range A. Particles suspended in the probe volume 16a move in response to sound waves 20 generated in an atmospheric bad weather condition at a distance B from the concentrated telescope 74, and the light scattered by these particles Forms a return beam 76, is collected by the concentrated telescope 74, and collimated by the beam expander 72. In addition, the sound waves arriving in a direction close to the vertical plane of the remote sensing beam 76 provide refractive index coupling. However, due to the insensitivity of the refractive index coupling to particle motion coupling, sound waves arriving from the forward looking direction provide the dominant form of coupling. Nevertheless, refractive index coupling may be used to provide lateral coverage in the form of port / starboard and up / down to provide longitudinal particle kinetic coupling within the probe volume 16a. Can be.
Return beam 76 is then turned on / off Kerr-cell electro-optic (EO) transmission / reception (t / r) by time scale tracking device 28. Deflection at the switch and range gate 80. In this way, the time pulsed operation of the EO pulse modulator 24, delay device 48 and gate 80 are all controlled correspondingly by the tracking device 28 and the moment of the aircraft towards the probe volume 16a. The probe volume is sensed over a period of time required to calibrate the movement to collect a plurality of laser pulses. The tracking device 28 shortens the out-of-time pulse repetition rate at the pulse coding driver 26 and the gate 80, and the signal 50 moves as the aircraft moves towards the probe volume 16a and the distance A decreases. The delay of the reference beam 54a coincides with the change in the round trip time delay of the laser pulse caused during transmission and reception via the transmission beam 34a and the return beam 76, respectively. The concentrated telescope 74 will be installed on a movable platform, such as a gimbled inertial platform, and as the aircraft moves toward the probe volume, to maintain the beam aimed at the probe volume 16a. Will be moved in synchronization with the tracking device 28. In addition, the tracking device 28 corrects the laser reciprocating travel time pulse to pulse a variable related to the refractive index change caused by the scalar turbulence fluctuations in changes due to temperature, humidity, pressure, etc. in the atmosphere adjacent to the aircraft front. do.
In addition, since there are no multiple pulses processing the length of the probe volume, a single pulse duration will be suppressed by particle motion (PM) Doppler frequency spreading. In accordance with single pulse coding by the pulse coding driver 26, the shorter probe volume can also be adjusted by processing the N-pulse.
The return beam 76 passes through the distance gate 80 and branches through the wavefront curvature diverging optical lens 82 into a plurality of beams 84 on the front surface of the 3-D curved offset axis reflector 86, the reflector 86 reflects a plurality of beams 84 on the pixels on the front surface 89 of the CCD 87, respectively.
The reference beams 54a branch through the similar lens 88 to the same number of reference beams 90 as the beams 84 on the rear of the reflector 86, each recorded in the pixels of the associated CCD 87. Time and wavelength, in this respect, heterodyne mixed with multi-channel signal information derived from return beam 84. In this way, angle-diversity reception (ADR) is applied to the common probe volume 16a, with each ADR multichannel intersecting a "speckle" that intersects the surface of the image plane of the CCD 87. The probe volume is viewed from a sufficiently different angle to average the "unresolved" components of sonic and subsonic noise that appear as There are an additional plurality of identical processing channels associated with each brob volume 16b, 16c, and the like.
CCD 87 has approximately 100 x 100 or 10 4 pixels on its front surface 89, consistent with suppressed particle Brownian motion in the atmosphere, and return beam 84 and reference beam 90 optically Heterodyne mixed on each pixel. As an alternative to homodyne mixing, which requires four times as many CCD pixels to apply spatial filtering to remove unwanted mixtures, the CCD 87 is an on-the-chip analog bandpass filter. 91 and on-the-chip analog to digital converter 92. The bandpass filter allows a returning mixture 84, e.g. a reference beam 90, containing the necessary mixture, e.g., instantaneous Doppler information, but an unnecessary mixture, returning beam 84 x returning beam 84 or a reference beam. (90) The reference beam 90 is rejected. As a result of the time recording provided by the path length of matching the reference beam 90 with the return beam 84, the coherent optical heterodyne mixing process performed on the surface of the CCD 87 is performed by a replica correlator. Play a role. The bandpass filter 91, which is applied to select the return beam 84 x reference beam 90 containing the instantaneous Doppler signal that is the desired mixture, electronically defines a more limited range-resolution pulse envelope than the original coded laser pulse. It compresses the returned coded laser pulses to provide, and also possesses a frequency deflection range of the instantaneous Doppler (eg, phase rate) modulated signal and noise. This Doppler modulation information is obtained through a phase rate demodulation process consisting of phase demodulation combined with phase unwrapping 96, spatial mean 98, and digital time derivative 100 to obtain phase rate information from ADR processing. Lose. This wide band phase rate demodulation is more suitable for this particular function of providing Doppler as well as range information in the replication correlation process, as opposed to using a conventional bank of Doppler bandpass filters. The coded laser pulse compression removes some of the previously mentioned constraints in selecting the laser pulse length. Thus, the duration of the distance gate 80 is collapsed to further reject sonic and subsonic noise, otherwise the PM will combine into a longer equivalent probe volume. The addition of N-pulse processing extracts and maintains "fine grain" PM Doppler spread information imprinted in the Doppler "comb" spectral region of the spectrally defined digital IQ data stream around zero frequency. The application of this N-pulse moving target indicator (MTI) radar type processing allows a single pulse spectrum to be subdivided into "combs with N-tooth", each tooth having a PM Doppler frequency. Replication of the spread spectrum. Otherwise, in the case of a single wideband pulse, the desired Doppler modulation spectrum will be completely corrupted due to the interpolation with the pulse spectrum. In addition, the frequency band due to "shot" noise is uniformly defined. Depending on the N-pulse processing results, the bandwidth of the coded laser pulses may be selected to provide shorter radiation range resolution probe volume than by a single pulse processing. The on-the-chip analog to digital converter 92 is a means for applying a minimum sample clock rate requirement for creating a multi-pixel, multi-channel digital IQ data stream 94, on each pixel. Quadrature pulse undersampling of the bandpass filter is used to obtain inphase (I) and quadrature (Q) samples. The CCD 87 and its detailed operation can be conveniently referred to as a Charge-Coupled Angle Diversity Receiver Extraction by Correlating Optical Replicas for Phase Sensing (CADRE-CORPS) camera.
The multi-channel ADR system provided by the CCD 87 reduces the “speckle” noise from the probe volume 16a and is a single channel laser as described for each probe volume shown in Jacob's patent. Improve system sensitivity beyond the Doppler speedometer. "Speckle" noise is due to the High-Burst Density (HBD) situation. The HBD situation occurs when photons are returned to the optical receiver from many light-scattering particles that simultaneously occupy the probe volume 16a. Multiple light paths through which light rays can be returned from the particles cause a "speckle" pattern to be distributed across the receiving point on the image plane.
The "speckles" arise as a result of constructive and destructive interference between the multiple light paths. Such "speckles" fluctuate in amplitude because the particles rearrange themselves in the probe volume 16a. Thus, by looking at a large number of particles in probe volume 16a from sufficiently many obverted angles that coincide with photodetection point diffusion, such as a mosaic intersecting the image plane, to sample many statistically independent “speckles”, Speckle "noise can be significantly reduced by combining the phase rate estimates extracted from each CCD. Except for this method, when the laser center frequency is shifted (with sufficient incidental change in the wavelength of light), the "speckle" pattern changes and is less spatially correlated. Therefore, the "speckle" noise can also be reduced by combining the phase rate estimates extracted from the probe volume simultaneously illuminated with sufficiently many separate laser-light frequencies. This is the principle of frequency diversity receiver (FDR) processing that can be combined with ADR processing to provide additional "speckle" noise suppression.
The system of the present invention includes a coherent optical receiver to obtain a phase rate estimate of instantaneous Doppler-frequency modulation given by particle motion through probe volume 16a. The "speckle" noise due to amplitude fading manifests itself in one of several ways when coherent processing is used. This "speckle" is used to account for changes in changing particle motion (as well as refractive index deviations along the optical path connecting through each particle) due to disturbing mechanisms with length scales smaller than a particular dimension of the probe volume. Reflect. This movement is said to be "not solved" by the system. Conversely, a movement with a length scale larger than the probe volume causes all particles in the probe volume to move together without inducing "speckle" fading. Such a movement is said to be "solved" by the system. The "resolved" component includes sonic field modulation recovered for subsequent processing, while the "unresolved" component exhibits "speckle" noise. The “solved” components alternately exhibit noise fluctuations around their average phase rate deviation; One of these average value amounts varies in proportion to the sound-field deviation detected by the system.
When the data stream 94 is fed to the digital phase estimator 96, it incorporates a digital "phase unwrapping", which is then passed to the digital time derivative 100 through the spatial averager 98 to obtain a phase rate. . "Phase unwrapping" in the phase estimation process 96 is for ease in ADR processing. To this end, the present invention corresponds that the narrow band PM and RI noise mechanisms correspond to things such as velocity and scalar atmospheric turbulence fields, respectively. The "phase jump" due to the arctangent discontinuity is due to the "spike" generated during the phase rate demodulation process as induced equally after the digital time differentiator 100.
Prior to understanding this action as incorporated into the present invention, the consequent “spectral spreading” now known to be caused by the arc tangent discontinuity inherent in phase rate demodulation has previously been known rather than fading in-phase (I) components. It has been believed that there is a root cause for amplitude. Thus, the present invention separates phase rate demodulation into phase demodulation with " phase-unwrapping " logic included in digital time differential 100. “Phase unwrapping” can be accomplished by detecting when a discontinuity is encountered, storing data from around an offending region, then deleting the region, removing phase jumps, and evening it out. This is to derive the "non-spectrally-spread" phase rate estimate from the "unwrapped phase" estimate.
Therefore, this form of ADR processing is necessary to suppress the "unresolved" component of atmospheric particle Brownian motion below the "resolved" component level, which is generally below the "resolved" ambient acoustic noise background level. It does not bear the spatial average 98, which requires 100 x 100 = 10,000 multiple channels. This requires 40 dB suppression of unresolved Brownian motion noise, consistent with 100 x 100 = 10,000 multichannel ADR processing. Without "phase unwrapping," "spectral spreading" of unresolved components of speed and scalar (eg, temperature and specific humidity) fluctuations due to turbulence provides approximately 60 dB of "unresolved" noise suppression. In order to do this, it is necessary to use an ADR having about 1,000 × 1,000 = 1,000,000 multiple channels.
The data stream signal 102a provided by the digital time differentiator 100 has digital information regarding the phase rate modulation state that occurs in the probe volume 16a. Similarly, data streams 102b, 102c, etc., are generated for the probe volumes 16b, 16c. The data stream is provided to a time domain digital beam forming device 104 that magnifies (reduces) the focus over a predetermined acoustic range. The device generates a plurality of multi-channel beams 106, for example 128 channel beams, and generally matches the number of probe volumes with the beam 106 distributed over azimuth and elevation depression angles. Is designed. In addition, the acoustic range focus can be scanned over the entire radiation range in the form of a time-lapse for display 112. The beam 106 proceeds to the processor 108 which processes the beam information and simultaneously performs three-dimensional detection, grading, positioning and tracking of the bad weather condition at the separation distance B. This processed beam 110 indicates a sonic-contact intensity in the form of color coding in which the pair of azimuth and elevation horizontal angles and the aircraft are displayed in various two-dimensional boundary zones including a range of safe bad weather conditions. Is transmitted to a pilot visible display panel 112. In addition, the three-dimensional color display examines the elapsed time that the image is enlarged (reduced) over the entire emission range, and can describe the weather change in three-dimensional view of the information on the azimuth and elevation / horizontal angles. Such a display may be fixed to a specific area of focus by the user's choice.
Although the PM coupling system 10 has been described and illustrated in many uses directly at the front of the aircraft, a simple version of the system is installed on the ground at the end of the airport runway where a laser beam is projected along a path close to the airport runway. Can be. Ground systems do not require pulse tracking and beam stabilization because they are fixed on the ground rather than on a moving aircraft.
The entities of the SOCRATES invention shown in FIGS. 4 and 5 apply across airport runway 128 and in other cases respond to sound waves 150 offset parallel to the airport runway and generated by various flight pollution hazards. The terrestrial system 180 using refractive index (RI) coupling is shown. This terrestrial system 180 employs a segmented optical line arrangement utilizing a retroreflector (SOLAR) and is provided with a plurality of spaced apart at regular intervals from the communication lines across the runway and located in an offset position parallel to the runway 128. Adjustable leveling tripods 182, 184, 186 and 188. The two axis pairs of such a system are called binary segmented optical line arrays using BINARY SOLAR and can be directed at right angles to each other. In this way, an overlapping area that forms a plurality of steerable beams in two axis pairs can be used to provide additional positioning capability to the system.
Mounted on the tripod 182 is a combination laser transmitter and coherent light that transmits the laser beam 191 to an external light corner reflector 192 that is mounted on the right end tripod 188 and cooperatively totally reflects. Receiver module 190. Each of the intermediate tripods 184 and 186 has equally partially reflecting retroreflectors 194 and 194a, each of which will reflect back some of the beam 191 to the transceiver 190. As shown in FIG. 5, each retroreflector 194, 194a, etc. includes a center hole 196 in which the transmitter beam 191 reaches the corner reflector 192 and returns to the transceiver 190. The retroreflector also includes one of the holes 198, including a rotatable light deflection arm 200 that utilizes some or all of the light holes 198 and reflective mirrors spaced at equal intervals on the circumference. A portion of the transmitted beam reflected through the reflection is reflected to the transceiver 190. For example, in retroreflector 192, arm 200 is aligned to one of holes 198 to provide reflective beam 202 at one of the radiation locations of receiver 190. In the retroreflector 194a, the arm 200 is aligned with another hole 198 radially branched from the hole of the retroreflector 194, which is branched at a constant angle and does not interfere with the return beam 202. To provide.
The number of intermediate pedestals (184, 186, etc.) and the associated partial retroreflectors (194, 194a, 194b, etc.) is about 32 and return light beams (202, 204, etc.) spaced at regular angles on the circumference. Is provided back to the photodetector 204, which is circularly spaced apart on the transceiver 190, in such a way that each return light beam does not interfere with the other partially retroreflected light beam. The beam returning from the 100% corner reflector 192 returns along the central optical path through the center hole 196 of the retroreflectors 194, 194a, 194b, etc., on each arm 200. The selected number of cascade neutral density optical filters 210 can be uniformly provided by adjusting the attenuation of each optical path.
Accurate alignment of the corner reflector 192 and retroreflectors 194, 194a is performed using the instrument's lidar or optical radar target localizer mechanism, thereby radiating each arm 200 and selection hole 198. Connect the light beam of light returning through its respective position formed at the position. Of course, the reader's reader or optical radar target localizer has an alignment telescope and pulsed laser that precisely aligns the fine beam and enhances receiver capabilities. First, the surveyor places the pedestal 188 and corner reflector 192 at a desired location, and then the middle pedestal (186, 184, etc.) and retroreflectors 194a, 194, etc., from right to left, as shown in FIG. By adjusting, the center hole 196 and the circular hole 198 of all retroreflectors align appropriately. Next, the beam 191 will be correctly aligned with the center hole 196 and the corner reflector 192 by adjusting the facet 182 with the position transmitter receiver module 190. Next, the light deflecting arm 200 of each retroreflector is properly rotated to the selected angular position so that the beams returning from each retroreflector 194 are returned radially branched from the other retroreflectors 194, 194a, 194b, etc. Does not cause interference
The SOLAR system 180 provides an optical line arrangement that can form an acoustic multi-beam or beam adjustable response pattern 220. The pattern response formed by such a beam can receive and position the distant sound source 150 to rule out local sound speed and subsonic interference. A parallel back-up arrangement can be provided for a pair of SOLAR systems called twin segm ented optical line arrays using retro reflectors (TWIN SOLARs) using retroreflectors. This arrangement allows for the reception of sound speed energy from the runway approach passage while excluding back-lobe sound speed energy arriving from the aircraft engine, in particular while applying an engine propulsion inverter after the plane has landed on the runway. Is moved step by step.
The light deflecting arm 200 of the retroreflector 194 is undisturbed through the arm to a hole 198 which returns a predetermined portion of the transmission beam 191 to the transceiver 190 " spool center line. (spool center line) " is provided by a partially reflective mirror extending along the path. A set of neutral density light filters 210 are selectively switched in the radiant light beam path along the arm 200 to provide a particular retroreflector 194. The amount of light reduction required in steps is quantized. By performing such quantization, each of the partially reflective retroreflectors 194, 194a, etc. can adjust to return the same number of photons as the average number of photons returned by the total reflection corner reflector 192. The arm 200 of a particular retroreflector 194 is clicked and positioned radially in the selected hole 198 such that the partial retroreflector attenuates the preselected light to provide a mutually exclusively deflected return light beam to provide the light. It is preset to match the piston of the partial light retroreflector in the line array. Each return light beam is radially aligned and passes through the unoccupied peripheral hole 198 of the retroreflector 194, 194a, etc. between its individual photoreceive photodetectors 204. The plurality of return light beams are arranged circumferentially on the circular light receiving surface of the transceiver 190.
The SOLAR system described above can form a constantly adjustable beam and can apply optimal or adaptively controlled complex weights to the segments. This can be done by applying a vector matrix that collects the light returning from all retroreflectors to control the beam nulls or cancel the sound speed or subsonic noise.
The time to move along the laser beam and the return beam separately varies according to the compression and lean of the instantaneous sound waves 150 generated in the plane due to deterioration of weather such as wake vortex, downdraft, and updraft, The change in refractive index indicates the direction in which sound is emitted and reached in this dangerous state to provide a change in travel time. In addition, this travel time change provides a mechanical characteristic of the source that generates the sound according to the time waveform distortion of the instantaneous sound wave.
In an RI combining system that simply applies a transceiver such as module 190 and corner reflector 192 to produce one traveling-return light beam, the resulting negative response pattern bisects bistable angles to maximize response. It has an X / X characteristic wrapped around a common axis of an axis (MRA) or monostable angle system, and is disposed symmetrically about the axis around it. A disadvantage of this traveling-return light beam system is that in such an optical line arrangement, the negative response pattern cannot adjust the beam to move its MRA away from its normal position to a common axis or bisec of the traveling-return beam. In contrast, the SOLAR system 180 described above can overcome this disadvantage by providing a plurality of constant and adjustable beams.
When an optical line array is installed for clear beamforming / beam adjustment from the upper part of the frequency band to a predetermined frequency, the 1/2 acoustic wavelength or small interval (determined by the upper frequency band) moves the beam farther in the extension direction. It is necessary when adjusting. This is necessary to avoid indistinct lattice lobes due to rabbit-ears beam splitting, and the rose petal pattern, which is more complex by that spacing, increases the acoustic wavelength.
While adjusting the beam in the extension side direction, the extension side beamwidth is provided by the inverse of the disturbed acoustic wavelength along the outer traveling-returning light beam path length. By approaching the beam adjusting direction, because of the gap reduction effect, the acoustic beam response is enlarged. In addition, the source beam is formed with MRAs that point equally in both endfire directions without reducing the spacing to a quarter of the sound wavelength. At quarter sound intervals, this provides the need for at least 16 or suitably 32 pedestal and partially reflective retroreflectors and an external 100% reflective retroreflector. Each of these retroreflectors would be a passive optical device.
With the SOLAR method, beamforming can be very complex because the longer segment is then superimposed on it as each segment is filled. This complexity is because the acoustic response pattern associated with a particular partially reflective retroreflector is typically determined by the unidirectional optical path length between the contrasted laser transmitter / coherent optical receiver and the retroreflector. In terms of overall acoustic response, a general segmented sensor acoustic response can be derived by subtracting from the phase-to-reflector segment's phase-rate modulation that overlaps the phase-to-reflector segment's phase-rate modulation (PRM). Complex weights can likewise be derived by weighting other PRM components to selectively extract sonic noise from the sonic signal. As a result, they are not present in discretely located sonic noise sources. However, when the subsonic noise source is superior, this arrangement does not get the best gain by suppressing the subsonic noise over the sonic noise. When the optimal complex weight is applied to the overlapping segment components when the subsonic noise is superior, this complex weighting has a magnitude proportional to each overlapping segment length.
Regardless of the complexity of the beam forming, suitable beam shape, pointing, side lobe control and null control can be performed. In addition, a plurality of SOLAR or BINARY SOLAR or TWIN SOLAR segment light line arrays may be arranged to make a 2-D or 3-D array configuration. Then, by applying a suitable phase (as a frequency function) or time delay, frequency or time domain beamforming including real weights or complex weights for sidelobe or null control can affect the sharp application of the beam.
Another embodiment of the present invention is shown in FIGS. 7 and 6, applied to extend across an airport runway 128, and also using a refractive index (RI) responsive to sound waves generated by various flight pollution hazards. A simple ground system 120 is shown.
The system 120 supports a pair of triangular rod frames 130, 132, 134 and 136, respectively, and a pair of left and right pedestals 122 and 124 separated laterally with little reaching both ends of the airport runway 128. Of intermediate pedestals 126 and 127, the edges of the frame being aligned with each other and adjoining three segments adjacent thereto.
Each corner of the left end frame 130 transmits a laser beam to the total reflection edge retroreflector 140 aligned on the frame 136, and further receives a return beam reflected from the retroreflector 140 There is). When using a light beam splitter along the optical fiber, the light intensity generated from a very strong CW laser can be distributed to three transmission positions 140 at the corners of the frame 130. The time traveled along the laser beam is changed according to compression and lean of the instantaneous sound wave 150 generated during flight in bad weather conditions such as wake vortex, downdraft, and updraft. In addition, this travel time provides a fundamental mechanism for making these notes according to the temporal waveform excursions of the sound waves at that moment.
In order to make the horizontal position measurement accurate, other basic forms of the entity provide a partial retroreflector 152 mounted at each corner of the frame 132 and a partial retroreflector 154 mounted at each corner of the frame 134. do. Retroreflectors 152 and 154 are identical to retroreflectors 194 in FIG. 5, and the transmitter beams provided from each of the three modules 140 can reach or return to the corner reflector 142 mounted to frame 136. Are arranged to be. Some beams transmitted from the module 140 will be reflected back to the photodetector 156 on the frame 130 by the partial retroreflector 152. Similarly, some beams provided from module 140 will be reflected by some retroreflector 154 to photodetector 158 on frame 130. Light deflecting arms 196 of retroreflectors 154 and 152. Are radially located so that the beams returning from the retroreflector are radially branched and do not interfere with each other. The remaining major portion of the laser beam provided from module 140 passes through a cats-eye retroreflector 142 which is retroreflected to module 140. Thus, the mode in which the beam is collected has three sets of photodetectors 130 on the frame 130. The change in the refractive index of the light beam sensed by the photodetector is suitably processed to provide early warning information to the ground.
As described, other entities of the SOLAR method can manually limit the azimuth angle of arrival and the emission range for emitting acoustic waves 150. The sonic energy reaching from the phase center arrives between an auxiliary hole defined between the transmission / reception module located above and below the front of the frame 130, and the splitting reflector 152 located above and below the front of the frame with respect to the left auxiliary hole. Measure the delay time by the time difference. Similarly, the frame 34 is measured for the central auxiliary hole and the cats-eye retroreflector 142 is measured for the right auxiliary hole. That is, these two auxiliary holes partially overlap each other and are apparently divided into three but successive auxiliary hole responses are generated by differentiating adjacent auxiliary hole RI combined signal responses as described for SOLAR processing. Another embodiment measures the wavefront horizontal tilt and radius of curvature by substituting with a pedestal and determines the azimuth and radiation range instead of SOLAR, which permits beam forming or beam steering functions by subdividing the entire hole.
As described, the configuration of FIG. 6 for another embodiment of SOLAR is easy to evaluate the rise / fall angle from a wide range of vertical acoustic response patterns determined by the common vertical dimension of the left, middle and right auxiliary holes. To improve the accuracy of this system, the transmit / receive module 140 and the "cat's eye" retroreflector 142, with intermediate partial retroreflectors 152 and 154 coupled to photodetectors 156 and 158, respectively, may be used. Similar couplings are inserted in front of each frame 130, 136, 132 and 134. The various light beam paths between the vertical centers of the left, center and right auxiliary holes are similar to the light beam paths provided at the rear vertices of the frames 130, 136, 132 and 134. However, the auxiliary hole signal derived in this rear peak light beam path is used to cooperate with the corresponding plane surface light beam to remove the back load sonic response of each auxiliary hole.
FIG. 7 shows the cluster mode for the front center light beam path by indicating an additional 142 position to illuminate the right frame 136 mounted to the pedestal 124. In this way, the horizontally arranged auxiliary holes are divided into upper and lower auxiliary holes. The frame 136 and all corresponding frames are tilted vertically through a common angle so that the reflected sound wave that cancels the front sound wave 150 interferes with the ground surface 128 shifted 180 ° phase, so that each beam null is below. It can be used to compensate for the vertical beam tilt causing. Each up and down auxiliary hole overlaps the vertical beam response 172 up and down. In each region where the vertical beams overlap, the time delay difference between the vertical phase centers can be measured. In this way, the additional cluster mode shown in FIG. 7 improves the vertical angle measurement accuracy by measuring the rise / fall angles around the axis 173 across the beam from this delay time with respect to the forward tilt of the vertical wave. can do.
Without the overlapping acoustic vertical sensing beams 171, 172 across the front of the frames 130, 132, 134, 136, the system 120 detects sound waves 150 moving towards the frame, back to It only provides limited vertical angle estimation accuracy with back-to-front beam response suppression. As mentioned, the frame may also be slightly inclined upward to minimize interaction with the ground under the access corridor 128. Moreover, the overlapping acoustic vertical sensing beams 171, 172, along with a plurality of corresponding offset photodetectors, which may also be guided in association with each other in front of the frame 130, 132, 134, 136, the corner reflector 142 Is obtained as a result of a similar combination of transmitter / receiver module 140 with < RTI ID = 0.0 > and < / RTI > an appropriate light beam offset partial retroreflector 152,154. As mentioned, this additional beam cluster mode results in better vertical angle estimation precision by split beam processing of the vertical acoustic reception beams 171, 172. Beams 171, 172 are disposed around their intersecting axis 173. This system is called the SOLAR-ECLIPSE system. That is, the system is a segmented ray array using retroreflectors and provides altitude and curvature localization, which means the location of sonic emanations. It processes the horizontal and vertical slopes of the wavefront of the incident acoustic wave to obtain azimuth and elevation angle estimates with wavefront curvature that manually indicate the range.
Although the RI combination system described in Figures 4, 5, and 6 has been described for a particular use, such as a ground-based system, it is also possible to use the system in an aviation configuration. For example, the end-to-end of an aircraft wing, the left wing end to the left wing fuselage-right fuselage to the right wing end, or the upper fuselage tip, ie the cockpit tail and the upper end of the aircraft vertical stabilizer. The former RI coupling configuration covers just the front or rear of the aircraft, while the latter configuration provides RI coupling of acoustic signals arriving from the left or right direction of the aircraft. Each of these methods may be suitable for several applications, but the particle motion coupling system described in FIGS. 1-3 is suitable for aviation systems.
In another variant embodiment it is possible to include the use of an optical fiber cable configured as an optical waveguide. The fiber optic cable responds to the acoustic excitation strain along the length of the fiber, and the change in its corresponding fiber cross-section leads to a change in the fiber refractive index. This includes any method that uses electro-optical or other techniques to form optical code pulses. The optical code pulses are returned to the optical or photodetector coherent heterodyne or homodyne receiver, for example, through Rayleigh or Mie optical pseudoscattering due to random or definite distributed occlusion inherent in the fiber. . In these methods it is easy to use pulse decoding, which collapses the light pulse with electro-optic or electronic band gating as a means of depicting individual extended microphone sensor segments. In a similar manner to the use of free light waves in the SOLAR system method, some of the light waveguide methods may place these extended microphone sensors adjacent across the acoustic sonic opening. By using the light beam of the embodiments of FIGS. 1-7, the refractive index changes of the optical fiber waveguide caused by the emitted sound may imply dangerous atmospheric conditions that produce the sound.
In another variant, it may be possible to include an acoustic microphone installed at the tip of each wing of the aircraft or parallel or offset to the runway to detect sound waves generated by dangerous weather conditions and / or wake vortex.
In addition, the embodiment described in FIG. 3 may be modified in place of any type of optical system called PHARAOH (phase rate assessment by optical holography) described herein. Here, the optical system is an all-optical multi-channel angle diversity receiver (ADR) using photons instead of electrons, and performs an operation similar to the coherent optical CCD type camera described above with respect to FIG. PHARAOH-type ADR processing does not require a CCD and instead uses an optically reduced two-wave mixing method (DTWM) that produces an orthogonal bi-optical carrier component of coherent optical heterodyne type, thereby electrically inducing I & Q components. It provides a similar function.
3, it is also possible to replace the angular diversity receiver with a frequency diversity receiver (FDR) for "unresolved" noise suppression. In addition, as an accessory to the pulse tracking device 28 of FIG. 3, it is also possible to provide a radio wave vector frequency filtering (WVFF) system. This system is intended to eliminate the "signal" masking effect associated with platform motion that causes the spectrum to extend into the signal frequency band of the subsonic noise component being "resolved". An alternative to the propagation vector frequency filtering method is signal-free reference (SFR) applied noise cancellation. In this technique it is possible to apply using coherent optical homodyne or heterodyne processing for "resolved" subsonic noise cancellation. All these embodiments can also be integrated into CADRECORPS or PHARAOH cameras.
Other embodiments of the present invention include using an acoustic sawtooth wave that is nonlinearly generated and in which the radiation region is concentrated to produce an acoustic light reflector (AOM) that operates as a retroreflector. Acoustic amplification sufficient to create an impact surface in a nonlinear acoustic sawtooth wave is obtained by transmitting a composite spectral waveform using a plurality of sets of phase locked pulsed acoustic carrier waveforms emitted from individual projectors in a large array of multiple speakers. Constructive interference occurs when these acoustic pulses are brought together and coherently added to a given concentrated area. The resulting acoustic peak pressure amplification produces a pressure discontinuity on the steeply steep wavefront, which is formed periodically through nonlinear acoustic interactions.
Nonlinear impact wavefronts of periodic steep slopes are accompanied by evenly inclined optical refractive index (RI) discontinuities. Each of these discontinuities functions as a light reflector, and when the acoustic wavelength is adjusted to a multiple of half of the light wavelength, the returned photoelectric intensity is amplified by Bragg scattering. Amplification can also be accomplished using a reinoculated Brillouin scattering (RBS) form using a technique called optical phase conjugation (OPC). Traditionally, RBS has been used to achieve a 100-fold reduction in Doppler frequency spread associated with instantaneous Brillouin scattering. By this instantaneous Brillouin scattering, when light emission is at a relatively low level, photons instantly generate isothermal fluctuations corresponding to photons that propagate widely and disappear. At higher levels of radiation, stimulated Brillouin scattering (SBS) is produced so that the directionality of the photons becomes more orderly and thus the Doppler generated through "photon motion" by the primary magnitude for instantaneous Brillouin scattering. Reduce frequency spread.
SBS used with the gas trapped in the optical waveguide to create an OPC mirror that was distorted enough to eliminate the optical wavefront distortion, whereby unlike the conventional mirrors, the original path through which light travels before impingement light is reflected Go back to. At the lower emission levels required by SBS, it is also possible to form other light diffractive materials, such as lead titanate, in order to generate a low speed formation corrected OPC mirror. This is accomplished by a process called a reduced four-wave mixing (DFWM) method. It is pointed out that this process of the reduced four-wave mixing (DFWM) type has been described in the context of nonlinear light processing applicable to PHARAOH.
It is possible for RBS to use very high light emission levels, which can be generated by correcting atmospheric light aberrations using OPC such that photons are directly generated by densified light. When used in combination with AOM, the RBS process “reseed” the laser light scattered from non-linearly generated nonlinear photons using the FWDM method. The combination of these two processes is intended to sharpen the optical RI discontinuity in such a way as to reduce the mirror reflection loss from becoming another normal impact wavefront thickness. Without RBS amplification, the discontinuity would not be a sufficiently small portion of one light wavelength. In combination with periodic nonlinear sonic Bragg scattering, the RBS amplified AOM provides an efficient "sky hook" mirror, so that the retroreflector can be accommodated within the aircraft's wing length fuselage size. It replaces the desire to limit aeronautical applications to RI combinations.
There may be other possibilities of using acoustic electromagnetic methods. In this method, electromagnetic energy is propagated as free or waveguided radio waves instead of light waves depending on the sound generated by atmospheric hazards. For example, certain systems may be used to explore an ongoing acoustic system created by air hazards in aviation. That particular system is a system recognized as an Extended Radio Acoustic Sounding System (ERASS), which utilizes a set of aggregated non-linear sound waves, together with Bragg scattering as described in AOM, using radio waves instead of light waves.
In another embodiment, it may be possible to include the use of induced radio waves, such as coaxial cables, for exploring sound fields through Bragg reverse scattering.
Accordingly, the embodiments herein should be considered without limitation in all respects as illustrated, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and accordingly All changes that come within the meaning and range of equivalency are intended to be included therein.
- A method of detecting bad weather conditions in the atmosphere that pose a danger to a flying aircraft and generate natural sound waves in the atmosphere,Providing a laser device for generating a light beam,Directing the light beam into a probe volume containing a light reflecting material that moves in response to the natural sound wave at a location away from the bad weather condition;Condensing light reflected from the material;Generating output information representing the natural sound wave and the bad weather condition from the focused light,And the probe volume acts as a virtual microsurface.
- 10. The method of claim 1, wherein the bad weather condition is in a waiting area spaced a considerable distance from the probe volume.
- The method of claim 1, wherein the reflected light is collected by a multi-channel receiver that detects random movement of each particle of light reflecting material in the probe volume.
- The method of claim 1, wherein the laser device is installed at the front of the aircraft and the probe volume is located at the front of the aircraft along the flight path of the aircraft.
- The method of claim 1, wherein the laser device is installed near an aircraft runway.
- A method of detecting bad weather conditions in the atmosphere that pose a danger to a flying aircraft and generate natural sound waves in the atmosphere,Generating a plurality of light beams,Directing each light beam at a location away from the bad weather condition to an associated probe volume comprising a light reflecting material that moves in response to the sound waves;Condensing light reflected from the material in each of the probe volumes;Generating a signal from the light collected from each of said probe volumes,Combining the signals to produce output information indicative of the nature and location of the natural sound wave and the bad weather condition;And the probe volume acts as a virtual microsurface.
- 7. The method of claim 6, wherein said bad weather condition is in a standby region spaced a considerable distance from said probe volume.
- 7. The method of claim 6, wherein the light reflected from each probe volume is collected by a multi-channel receiver that detects random movements of individual particles of light reflecting material in each probe volume.
- 7. The method of claim 6, wherein the light beams are generated by laser means installed in the front of the aircraft and the probe volumes are located in front of the aircraft along the flight path of the aircraft.
- A method of detecting a dangerous atmosphere that poses a danger to a flying aircraft and generates natural sound waves in the atmosphere,Providing a laser device for generating a light beam,Directing the light beam to a probe volume at a location away from the hazardous atmosphere;Measuring the effect of the natural sound wave on the light beam as an indicator of the dangerous atmospheric state,And the probe volume acts as a virtual microser.
- 12. The method of claim 11, wherein the laser device is installed at the front of the aircraft.
- 12. The method of claim 11, wherein the laser device is installed near an aircraft runway.
- 14. The method of claim 13, further comprising: directing a plurality of light beams horizontally and vertically spaced apart from each other across the runway, reflecting back to photodetectors, and determining the light beam as an indicator of the hazardous atmospheric state. And detecting a change in travel time.
- 15. The method of claim 14, wherein a portion of the light beam is reflected back to photodetectors spaced a selected distance across the runway.
- 15. The method of claim 13, further comprising: directing the light beam across the runway, the plurality of locations laterally spaced apart from each other across the runway to provide a plurality of return beams that are reflected back to photodetectors. Reflecting at each of the segments of the light beam and measuring a change in travel time of the light beam as an indicator of the dangerous atmospheric condition.
- 17. The method of claim 16, wherein the return beams are spaced at an angle along the circumference of each other so as not to interfere with each other.
- 12. The method of claim 11, further comprising: extending the light beam from a first position to a second position on an aircraft and between the first position and the second position to provide a plurality of return beams that are reflected back to photodetectors. Reflecting the segment of the light beam at each of a plurality of laterally spaced locations, and measuring a change in travel time of the light beam as an indicator of the dangerous atmospheric state. How to detect standby status.
- 19. The method of claim 18, wherein the return beams are spaced at an angle along the circumference of each other so as not to interfere with each other.
- A device for detecting a bad weather condition of the atmosphere that poses a danger to a flying aircraft and generates natural sound waves in the atmosphere,Laser means for generating a light beam,Means for directing the light beam to an atmospheric probe volume at a location away from the bad weather condition;Means for measuring the effect of the natural sound wave on the light beam as an indicator of the bad weather condition,And the probe volume acts as a virtual microsurface.
- 27. The bad weather condition detection apparatus according to claim 26, wherein the laser means is installed at the front of the aircraft.
- 27. The apparatus of claim 26, wherein the laser means is installed near an aircraft runway.
- 29. The system of claim 28, wherein the laser means produces a plurality of light beams spaced horizontally and vertically from each other to direct across the runway,Means for reflecting the light beams back to photodetectors and means for measuring a change in travel time of the light beam as an indicator of a dangerous atmospheric condition.
- 30. The apparatus of claim 29, comprising means for reflecting a portion of the light beam back to photodetectors spaced a selected distance across the runway.
- 29. The apparatus of claim 28, further comprising means for directing the light beam across the runway and a plurality of locations laterally spaced apart from each other across the runway to provide a plurality of return beams that are reflected back to photodetectors. Means for reflecting a segment of the light beam in each and means for measuring a change in travel time of the light beam as an indicator of a dangerous atmospheric condition.
- 32. The apparatus of claim 31, comprising means for spaced apart from each other along the circumference of the return beams so as not to interfere with each other.
- A device for detecting a bad weather condition of the atmosphere that poses a danger to a flying aircraft and generates natural sound waves in the atmosphere,Laser means for generating a light beam,Means for directing the light beam at a location remote from the bad weather condition to a probe volume comprising a light reflecting material that moves in response to the natural sound wave;Means for condensing light reflected from the material;Means for generating output information indicative of said natural sound waves and atmospheric conditions from said focused light,And the probe volume acts as a virtual microsurface.
- 34. The apparatus of claim 33, wherein the bad weather condition is in a standby area spaced a considerable distance from the probe volume.
- 34. The apparatus for detecting bad weather conditions according to claim 33, wherein the condensing means comprises a multi-channel receiver for sensing random movement of each particle of light reflecting material in the probe volume.
- 34. The apparatus of claim 33, comprising means for installing the laser means in the front of the aircraft, wherein the probe volume is in front of the aircraft along the flight path of the aircraft.
- 34. The apparatus of claim 33, comprising means for installing the laser means near an aircraft runway.
- 12. The method of claim 11, wherein the light beam is guided by fiber optic cable means.
- 27. The apparatus of claim 26, wherein the directing means comprises fiber optic cable means for guiding the light beam.
Priority Applications (4)
|Application Number||Priority Date||Filing Date||Title|
|US08/955,282 US6034760A (en)||1997-10-21||1997-10-21||Method of detecting weather conditions in the atmosphere|
|PCT/US1998/018589 WO1999021394A1 (en)||1997-10-21||1998-09-04||Method of detecting atmospheric weather conditions|
|Publication Number||Publication Date|
|KR20010031349A KR20010031349A (en)||2001-04-16|
|KR100566349B1 true KR100566349B1 (en)||2006-03-31|
Family Applications (1)
|Application Number||Title||Priority Date||Filing Date|
|KR1020007004343A KR100566349B1 (en)||1997-10-21||1998-09-04||Method of detecting atmospheric weather conditions|
Country Status (12)
|US (1)||US6034760A (en)|
|EP (1)||EP1040726A4 (en)|
|JP (1)||JP2001521161A (en)|
|KR (1)||KR100566349B1 (en)|
|CN (1)||CN1135901C (en)|
|AU (1)||AU753006B2 (en)|
|CA (1)||CA2308203C (en)|
|IL (1)||IL135735A (en)|
|NO (1)||NO321926B1 (en)|
|NZ (1)||NZ504575A (en)|
|TR (1)||TR200001100T2 (en)|
|WO (1)||WO1999021394A1 (en)|
Families Citing this family (65)
|Publication number||Priority date||Publication date||Assignee||Title|
|GB2321808B (en) *||1997-01-24||1999-03-17||Plessey Telecomm||Single sideband modulators|
|US6590661B1 (en) *||1999-01-20||2003-07-08||J. Mitchell Shnier||Optical methods for selectively sensing remote vocal sound waves|
|US6535158B2 (en)||2000-03-15||2003-03-18||Utah State University Research Foundation||Kinematic analysis of conically scanned environmental properties|
|JP3638862B2 (en) *||2000-08-01||2005-04-13||三菱電機株式会社||Turbulence detection device and turbulence detection method|
|US7148815B2 (en) *||2000-12-22||2006-12-12||Byron Scott Derringer||Apparatus and method for detecting objects located on an airport runway|
|WO2002061980A1 (en) *||2001-01-30||2002-08-08||University Of South Florida||Open-path/free-space optical communication system and method using reflected or backscattered light|
|JP3633499B2 (en) *||2001-03-23||2005-03-30||三菱電機株式会社||Back turbulence detection device and back turbulence detection method|
|US6646725B1 (en)||2001-07-11||2003-11-11||Iowa Research Foundation||Multiple beam lidar system for wind measurement|
|US20030206182A1 (en) *||2001-07-20||2003-11-06||Weather Central, Inc. Wisconsin Corporation||Synchronized graphical information and time-lapse photography for weather presentations and the like|
|US6856396B2 (en)||2001-10-10||2005-02-15||Swan International Services Pty||Wind shear detection system|
|US7106447B2 (en) *||2002-03-01||2006-09-12||Michigan Aerospace Corporation||Molecular optical air data systems (MOADS)|
|US7495774B2 (en) *||2002-03-01||2009-02-24||Michigan Aerospace Corporation||Optical air data system|
|US6870607B1 (en)||2002-03-05||2005-03-22||Joram Hopenfeld||Method and apparatus for analyzing information from sensors provided over multiple optical waveguides|
|GB0209053D0 (en) *||2002-04-22||2002-12-18||Bae Systems Plc||Method and apparatus for laser vibrometry|
|US6828923B2 (en) *||2002-11-22||2004-12-07||The Boeing Company||Airborne microwave/infrared wind shear and clear air turbulence detector|
|US20040174770A1 (en) *||2002-11-27||2004-09-09||Rees Frank L.||Gauss-Rees parametric ultrawideband system|
|US7359438B2 (en) *||2002-11-27||2008-04-15||Clifton Labs, Inc.||Optical communications imager|
|WO2004106971A1 (en) *||2003-05-30||2004-12-09||Mitsubishi Denki Kabushiki Kaisha||Coherent laser radar|
|US9244167B1 (en)||2008-03-07||2016-01-26||Rockwell Collins, Inc.||Long range weather information display system and method|
|US9244157B1 (en)||2008-03-07||2016-01-26||Rockwell Collins, Inc.||Weather radar threat depiction system and method|
|US9244166B1 (en)||2008-03-07||2016-01-26||Rockwell Collins, Inc.||System and method for ice detection|
|EP1673587A4 (en) *||2003-09-17||2010-03-24||Aeroflex Inc||Atmospheric turbulence hazard detector|
|FR2860300B1 (en) *||2003-09-25||2006-01-27||Formulaction||METHOD AND DEVICE FOR ANALYZING MOTION IN A DIFFUSING MEDIUM.|
|US20050258346A1 (en) *||2004-05-21||2005-11-24||Silicon Light Machines Corporation||Optical positioning device resistant to speckle fading|
|US7773070B2 (en) *||2004-05-21||2010-08-10||Cypress Semiconductor Corporation||Optical positioning device using telecentric imaging|
|US7126586B2 (en) *||2004-09-17||2006-10-24||Microsoft Corporation||Data input devices and methods for detecting movement of a tracking surface by detecting laser doppler self-mixing effects of a frequency modulated laser light beam|
|EP1693668A1 (en) *||2005-01-27||2006-08-23||Siemens Aktiengesellschaft||Method and Apparatus for determining defects in turbine parts|
|US7417578B1 (en) *||2005-03-08||2008-08-26||Rockwell Collins, Inc.||Removal of spurious aircraft detections on weather radar|
|US7251196B1 (en)||2005-05-31||2007-07-31||The United States Of America As Represented By The Secretary Of The Navy||Passive optical detection of underwater sound|
|US7561813B2 (en) *||2005-06-09||2009-07-14||Northrop Grumman Corporation||Wide field of view heterodyne receiver|
|FR2891802B1 (en) *||2005-10-11||2009-03-13||Airbus France Sas||Method and device for attenuating the effects of vertical turbulence on an aircraft|
|US7737948B2 (en) *||2005-12-20||2010-06-15||Cypress Semiconductor Corporation||Speckle navigation system|
|JP4859208B2 (en) *||2006-03-03||2012-01-25||独立行政法人 宇宙航空研究開発機構||How to detect turbulence|
|US7728816B2 (en) *||2006-07-10||2010-06-01||Cypress Semiconductor Corporation||Optical navigation sensor with variable tracking resolution|
|US7686253B2 (en) *||2006-08-10||2010-03-30||The Boeing Company||Systems and methods for tracing aircraft vortices|
|US7551519B2 (en) *||2006-12-21||2009-06-23||Dan Slater||Passive long range acoustic sensor|
|WO2009063322A2 (en) *||2007-08-15||2009-05-22||Malvern Instruments Ltd||Broad-range spectrometer|
|FR2921635B1 (en) *||2007-09-27||2010-06-04||Eurocopter France||Method and device for detecting and signaling the approach of the vortex domain by a giravion|
|US8902100B1 (en) *||2008-03-07||2014-12-02||Rockwell Collins, Inc.||System and method for turbulence detection|
|US9846230B1 (en)||2013-03-15||2017-12-19||Rockwell Collins, Inc.||System and method for ice detection|
|US9535158B1 (en)||2013-11-21||2017-01-03||Rockwell Collins, Inc.||Weather radar system and method with fusion of multiple weather information sources|
|US8541727B1 (en)||2008-09-30||2013-09-24||Cypress Semiconductor Corporation||Signal monitoring and control system for an optical navigation sensor|
|FR2942043B1 (en) *||2009-02-06||2011-02-11||Thales Sa||System and method for detecting and determining remote atmospheric anomalies.|
|US8711096B1 (en)||2009-03-27||2014-04-29||Cypress Semiconductor Corporation||Dual protocol input device|
|FR2948463B1 (en) *||2009-07-22||2011-10-07||Airbus Operations Sas||Lidar boots bi-mode|
|US9223020B1 (en)||2010-09-28||2015-12-29||Rockwell Collins, Inc.||System and method for weather detection using more than one source of radar data|
|CN101976078A (en) *||2010-09-29||2011-02-16||清华大学||Unmanned helicopter automatic landing method based on laser guidance|
|CN102288578B (en) *||2011-07-26||2013-02-13||中国科学院安徽光学精密机械研究所||Transmission type optical fiber turbulence sensor|
|US9019146B1 (en)||2011-09-27||2015-04-28||Rockwell Collins, Inc.||Aviation display depiction of weather threats|
|US9057773B1 (en)||2012-12-06||2015-06-16||Rockwell Collins, Inc.||Weather information display system and method|
|US9599707B1 (en)||2014-01-23||2017-03-21||Rockwell Collins, Inc.||Weather radar system and method with path attenuation shadowing|
|US9864055B1 (en)||2014-03-12||2018-01-09||Rockwell Collins, Inc.||Weather radar system and method for detecting a high altitude crystal cloud condition|
|US9823347B1 (en)||2014-03-12||2017-11-21||Rockwell Collins, Inc.||Weather radar system and method for high altitude crystal warning interface|
|US9810770B1 (en)||2014-07-03||2017-11-07||Rockwell Collins, Inc.||Efficient retrieval of aviation data and weather over low bandwidth links|
|US9709671B1 (en) *||2014-08-19||2017-07-18||Dan Slater||Electrosound camera|
|US9869766B1 (en)||2015-01-28||2018-01-16||Rockwell Collins, Inc.||Enhancement of airborne weather radar performance using external weather data|
|US10222253B2 (en) *||2015-07-14||2019-03-05||Lawrence Livermore National Security, Llc||UV laser based stand-off acoustic sensor|
|US10809375B1 (en)||2015-09-14||2020-10-20||Rockwell Collins, Inc.||Radar system and method for detecting hazards associated with particles or bodies|
|US10302815B1 (en)||2015-10-01||2019-05-28||Rockwell Collins, Inc.||System and method of integrating global convective weather|
|RU2617459C1 (en) *||2015-10-26||2017-04-25||Акционерное общество "Научно-производственное объединение "Государственный институт прикладной оптики" (АО "НПО ГИПО")||Multichannel optical-location system|
|CN105606195B (en) *||2016-01-20||2018-08-14||上海交通大学||Based on the grains of sand Ultra-low Frequency Vibration Sensor with lens fiber array|
|US9906870B2 (en) *||2016-02-15||2018-02-27||Aalap Rajendra SHAH||Apparatuses and methods for sound recording, manipulation, distribution and pressure wave creation through energy transfer between photons and media particles|
|US10494108B1 (en)||2016-05-17||2019-12-03||Rockwell Collins, Inc.||System and method for providing icing condition warnings|
|US10802107B2 (en) *||2017-01-23||2020-10-13||United States Of America As Represented By The Administrator Of Nasa||Adaptive algorithm and software for recognition of ground-based, airborne, underground, and underwater low frequency events|
|CN107957595A (en) *||2017-12-06||2018-04-24||郝明学||High-altitude air blast remote probe instrument|
Family Cites Families (42)
|Publication number||Priority date||Publication date||Assignee||Title|
|US3540829A (en) *||1968-09-09||1970-11-17||Bell Telephone Labor Inc||Laser detection of clear air turbulence|
|US3665467A (en) *||1969-11-19||1972-05-23||Nasa||Clear air turbulence detector|
|US3738750A (en) *||1970-12-10||1973-06-12||Us Air Force||Doppler shift laser velocimeter data processor|
|US3693015A (en) *||1971-01-08||1972-09-19||Buford H Funk Jr||System for monitoring air vortices comprising plural schlieren detectors with output signals added and rms value of sum produced for indication of turbulance|
|US3723004A (en) *||1971-05-18||1973-03-27||Us Air Force||Laser velocimeter employing dual scatter detection|
|US3825341A (en) *||1971-06-11||1974-07-23||Tokyo Shibaura Electric Co||Doppler radar using laser|
|US3800906A (en) *||1972-08-22||1974-04-02||Us Navy||Laser heterodyne acoustic sensor|
|US5504719A (en) *||1974-09-19||1996-04-02||Martin Marietta Corporation||Laser hydrophone and virtual array of laser hydrophones|
|US3968362A (en) *||1975-08-11||1976-07-06||Honeywell Inc.||Optical system for laser doppler homodyne detection|
|US3984685A (en) *||1975-12-03||1976-10-05||Nasa||Wind measurement system|
|US4167329A (en) *||1977-12-12||1979-09-11||Raytheon Company||Focussed doppler radar|
|US4168906A (en) *||1978-04-19||1979-09-25||The United States Of America As Represented By The Secretary Of Commerce||Differential Doppler velocity sensor|
|US4195931A (en) *||1978-05-18||1980-04-01||The United States Of America As Represented By The Secretary Of The Army||Clear air turbulence detector|
|US4303862A (en) *||1979-07-18||1981-12-01||Geiger Allen R||Clear air turbulence detector|
|US4359640A (en) *||1979-07-18||1982-11-16||Aero-Geophysical, Inc.||Clear air turbulence detection|
|JPS6133470B2 (en) *||1980-05-30||1986-08-02||Rodosho Sangyo Anzen Kenkyujo|
|US4397549A (en) *||1981-03-27||1983-08-09||The United States Of America As Represented By The Secretary Of The Army||Method for removal of LIDAR background backscattering by subtraction of multiple-delayed return signal|
|US4483614A (en) *||1981-12-08||1984-11-20||Lockheed Corporation||Optical air data measurement system|
|US4506979A (en) *||1981-12-08||1985-03-26||Lockheed Corporation||Compact radiation fringe velocimeter for measuring in three dimensions|
|DE3322898A1 (en) *||1982-07-02||1984-01-05||Secr Defence Brit||Device for detecting winch shears|
|US4465372A (en) *||1982-09-23||1984-08-14||The Unied States Of America As Represented By The Secretary Of The Air Force||Turbulence measurement interferometer apparatus|
|US4589070A (en) *||1982-10-25||1986-05-13||R & D Associates||Airborne wind shear response system|
|US4932997A (en) *||1984-04-11||1990-06-12||Ciba-Geigy Corporation||N-heterocyclosulfonyl-N'-pyrimidinylureas and N-heterocyclosulfonyl-N'-triazinylureas|
|US4630051A (en) *||1985-03-01||1986-12-16||Holodyne Ltd., 1986||Imaging doppler interferometer|
|US4779222A (en) *||1985-04-22||1988-10-18||The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration||Laser Doppler Velocimeter multiplexer interface for simultaneous measured events|
|DE3518800C2 (en) *||1985-05-24||1988-12-15||Deutsch-Franzoesisches Forschungsinstitut Saint-Louis, Saint-Louis, Haut-Rhin, Fr|
|DE3520214C1 (en) *||1985-06-05||1986-07-10||Deutsche Forsch Luft Raumfahrt||Measuring device for determining the wind direction and wind speed in the atmosphere|
|US4652122A (en) *||1985-06-26||1987-03-24||United Technologies Corporation||Gust detection system|
|US4715707A (en) *||1986-04-03||1987-12-29||Mcdonnell Douglas Corporation||Laser doppler velocimeter with laser backscatter discriminator|
|US4996473A (en) *||1986-08-18||1991-02-26||Airborne Research Associates, Inc.||Microburst/windshear warning system|
|US4893923A (en) *||1986-10-06||1990-01-16||Laser Science, Inc.||Doppler laser radar system|
|DE3815474C2 (en) *||1988-05-06||1992-03-05||Deutsche Forschungsanstalt Fuer Luft- Und Raumfahrt Ev, 5300 Bonn, De|
|US5216478A (en) *||1989-03-31||1993-06-01||Canon Kabushiki Kaisha||Doppler velocity meter|
|FR2648915B1 (en) *||1989-06-26||1991-09-27||Centre Nat Rech Scient||Medium altitude wind speed measuring device|
|FR2663752B1 (en) *||1990-06-25||1993-01-22||Seso||Meteorological parameter measuring device.|
|US5523759A (en) *||1992-04-14||1996-06-04||Honeywell Inc.||In flight doppler weather radar wind shear detection system|
|US5221927A (en) *||1992-05-20||1993-06-22||The United States Of America As Represented By The Secretary Of Commerce||Lidar-acoustic sounding of the atmosphere|
|FI94559C (en) *||1992-07-30||1995-09-25||Vaisala Oy||Method and apparatus for measuring the visibility and light scattering in the atmosphere, in which apparatus a common optic is used for transmission and reception|
|US5394238A (en) *||1992-11-09||1995-02-28||Honeywell Inc.||Look-ahead windshear detector by filtered Rayleigh and/or aerosol scattered light|
|US5469169A (en) *||1993-11-30||1995-11-21||University Corporation For Atmospheric Research||Receiver for bistatic doppler radar network|
|JP3279116B2 (en) *||1994-03-22||2002-04-30||株式会社豊田中央研究所||Laser Doppler velocimeter|
|US5379270A (en) *||1994-03-25||1995-01-03||The United States Of America As Represented By The Secretary Of The Navy||Acoustic-optic sound velocity profiler|
- 1997-10-21 US US08/955,282 patent/US6034760A/en not_active Expired - Fee Related
- 1998-09-04 CA CA002308203A patent/CA2308203C/en not_active Expired - Fee Related
- 1998-09-04 AU AU10606/99A patent/AU753006B2/en not_active Ceased
- 1998-09-04 IL IL13573598A patent/IL135735A/en not_active IP Right Cessation
- 1998-09-04 EP EP98953163A patent/EP1040726A4/en not_active Withdrawn
- 1998-09-04 WO PCT/US1998/018589 patent/WO1999021394A1/en not_active Application Discontinuation
- 1998-09-04 JP JP2000517577A patent/JP2001521161A/en active Pending
- 1998-09-04 NZ NZ504575A patent/NZ504575A/en unknown
- 1998-09-04 TR TR2000/01100T patent/TR200001100T2/en unknown
- 1998-09-04 KR KR1020007004343A patent/KR100566349B1/en not_active IP Right Cessation
- 1998-09-04 CN CNB988114380A patent/CN1135901C/en not_active IP Right Cessation
- 2000-04-17 NO NO20001994A patent/NO321926B1/en not_active IP Right Cessation
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|US8797550B2 (en)||Atmospheric measurement system|
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|EP0648340B1 (en)||Obstacle avoidance system for helicopters and aircraft|
|US4123165A (en)||Attitude determination using two color, dual-sweeping laser system|
|US5485009A (en)||Laser imaging system with a linear detector array|
|DE10316762B4 (en)||Method for detecting wind speeds with a Doppler-Lidar system, in particular on board aircraft, and Doppler Lidar system|
|US3984685A (en)||Wind measurement system|
|US8665122B2 (en)||System for the detection and the depiction of objects in the path of marine vessels|
|EP1423730B1 (en)||Wide field scanning laser obstacle awareness system|
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|GRNT||Written decision to grant|
|LAPS||Lapse due to unpaid annual fee|